Flush-type light-emitting devices that are embedded in a floor of a store, restaurant, etc., and emit light from its surface (top surface) are known. This type of light-emitting device is able to produce artistic and decorative effects using light and give visual entertainment to the customers, etc.
However, the above light-emitting device is buried in a floor of a building and therefore generally installed during the construction of the building. Considerable work is required if the device is to be installed in an existing floor. Therefore, the conventional light-emitting devices could not promptly satisfy the needs for producing artistic or decorative effects using light only during an event held in a store or specific program presented in an exhibition venue, and the prohibitive construction expenses required to install this type of light-emitting device also made the device unsuitable for such applications.
To easily achieve floor lighting, lighting devices that can be installed on an existing floor have been proposed. This type of device has a box-shaped casing with an open top, a plate-shaped reinforced plastic material installed in the top opening of the casing, a plate-shaped light-diffusing member installed below the reinforced plastic material, and a fluorescent tube or other light source for irradiating the light-diffusing member. A commercial AC power supply is used as a power source for irradiating the light source. By arranging multiple light-emitting units in vertical and horizontal rows, a large lighting system can be configured.
To supply operating power to the light sources of multiple light-emitting units and also control the light sources individually, lighting systems equipped with a dimming console that outputs DMX signal and a dimming panel that has dedicated transformers for supplying power and data to the multiple light-emitting units are known. The dimming panel has a power cable for connecting to the commercial AC power supply (such as 100 VAC), an input terminal for connecting to the dimming console and inputting DMX signal, and multiple output terminals for outputting direct-current power (such as 24 VDC) and data in accordance with the control by DMX signal, and by connecting a light-emitting unit to each output terminal the panel can control multiple light-emitting units via DMX signal.
However, the above lighting device requires a relatively tall casing and the top face of the lighting device, or the actual floor of the building, is relatively high, because the reinforced plastic material, light-diffusing member and light source must be stacked on top of one another in the casing. This not only limits the location for installing alighting device in terms of the height of the ceiling or entrance/exit, but it also creates a large height gap between the sections where a lighting device is installed and not installed, thereby posing a concern over stepping up/down the device by people walking on top.
In addition, since the above lighting device utilizes a fluorescent tube as its light source, the color emitted from the surface material becomes a monotone color. As a result, it is not possible to emit a desired color or change the color with the passage of time. Consequently, this lighting device could not fully produce a full-scale light fantasy or illusion, either, to arouse excitement in the customers.
When the casing of the above lighting device has a rectangular solid shape, multiple lighting devices can be arranged in vertical and horizontal rows. In other words, by combining multiple lighting devices in accordance with the floor area of the installation location a large lighting system can be configured. However, since each lighting device has a power cable extending from it that supplies power to the light source, combining multiple lighting devices requires each power cable to be connected to mains power (outlet). This made the wiring of power cables more complex, reduces the aesthetic effects, and sometimes made it difficult to interconnect the lighting devices.
In addition, the reinforced plastic material installed in the top opening of the casing scratches easily due to contact with the edge of a heal or umbrella worn/held by people walking on top, and the scratched areas tend to become clouded. For this reason, there arise concerns that transparency would be lost with the passing of time, thereby making the illumination look darker despite the brightness of the light source remaining the same. There are also concerns that clouding would reduce the esthetic look. Surface clouding can be suppressed by using reinforced glass in place of reinforced plastic material, but glass is generally slippery and might cause people walking on top to trip.
In the conventional technology, in a lighting system configured by arranging multiple light-emitting units in vertical and horizontal rows, each light-emitting unit is connected directly to an output terminal on the dimming panel in order to transmit operating power and data from the dimming panel to each light-emitting unit. Therefore, the dimming panel has to include as many cables (power lines) as the number of light-emitting units, and these cables have the length required for connecting the light-emitting unit installed farthest from the dimming panel. This made it easy for the multiple cables to get tangled with one another and often resulted in a complex wiring layout. Particularly since the number and locations of light-emitting units vary depending on the size and shape of the floor on which they are installed, there are also cases where the cables are unnecessarily long or too short to connect the respective light-emitting units. Further, the complex cabling sometimes reduces the aesthetic effects and made it difficult to interconnect the light-emitting units.
In addition, the enclosure of the dimming panel used in the above lighting system is large because it has many transformers. This made it difficult to install the dimming panel near the installing system, and in many cases the panel has to be installed away from the light-emitting units or in an exposed condition. If the panel has to be installed away from the light-emitting units, an extension cable or other means is required, which added to the complexity of wiring. Further, installing the panel in an exposed condition often makes the appearance unattractive and consequently the artistic effect by light. Since the number of light-emitting units connectable to one dimming panel is not infinite but generally limited to around 20 units, multiple dimming panels are required when configuring a lighting system combining more light-emitting units and this limits the installation location.